ATmega162 Atmel Corporation, ATmega162 Datasheet - Page 34

• Manufacturer Part Number: ATmega162
• Manufacturer: Atmel Corporation

Specifications of ATmega162

• Flash (kbytes): 16 Kbytes
• Pin Count: 44
• Max. Operating Frequency: 16 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 16
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 35
• Ext Interrupts: 3
• Usb Speed: No
• Usb Interface: No
• Spi: 1
• Uart: 2
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Analog Comparators: 1
• Resistive Touch Screen: No
• Temp. Sensor: No
• Crypto Engine: No
• Sram (kbytes): 1
• Eeprom (bytes): 512
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -40 to 85
• I/o Supply Class: 1.8 to 5.5
• Operating Voltage (vcc): 1.8 to 5.5
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 4
• Output Compare Channels: 6
• Input Capture Channels: 2
• Pwm Channels: 6
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

Using all 64KB
Locations of External
Memory
34
ATmega162/V
Since the external memory is mapped after the internal memory as shown in
64,256 Bytes of external memory are available by default (address space 0x0000 to 0x04FF is
reserved for internal memory). However, it is possible to take advantage of the entire external
memory by masking the higher address bits to zero. This can be done by using the XMMn bits
and control by software the most significant bits of the address. By setting Port C to output 0x00,
and releasing the most significant bits for normal Port Pin operation, the Memory Interface will
address 0x0000 - 0x1FFF. See code example below.
Note:
Care must be exercised using this option as most of the memory is masked away.
Assembly Code Example
C Code Example
#define OFFSET 0x2000
void XRAM_example(void)
{
unsigned char *p = (unsigned char *) (OFFSET + 1);
DDRC = 0xFF;
PORTC = 0x00;
SFIOR = (1<<XMM1) | (1<<XMM0);
*p = 0xaa;
SFIOR = 0x00;
*p = 0x55;
}
; OFFSET is defined to 0?2000 to ensure
; external memory access
; Configure Port C (addr?ss high byte) to
; output 0x00 when the p?ns are released
; for normal Port Pin op?ration
ldi
out
ldi
out
; release PC7:5
ldi
out
; write 0xAA to address ?x0001 of external
; memory
ldi
sts
; re-enable PC7:5 for ex?ernal memory
ldi
out
; store 0x55 to address ?OFFSET + 1) of
; external memory
ldi
sts
1. The example code assumes that the part specific header file is included.
r16, 0xFF
DDRC, r16
r16, 0x00
PORTC, r16
r16, (1<<XMM1)|(1<<XMM0)
SFIOR, r16
r16, 0xaa
0x0001+OFFSET, r16
r16, (0<<XMM1)|(0<<XMM0)
SFIOR, r16
r16, 0x55
0x0001+OFFSET, r16
(1)
(1)
Figure
2513K–AVR–07/09
11, only